(astronomy) The eastern half of the northern constellation Serpens, said to resemble a snake. It is said to represent the tail end of the snake.

(anatomy) A bundle of nerve roots at the base of the spinal column

(paleontology) A plume-shaped fossil, supposed to be a seaweed, characteristic of the lower Devonian rocks.

A hot Piedmontese dip made from salted anchovies, olive oil and garlic.

(medicine) A condition resulting from damage to the cauda equina, with symptoms including low back pain, pain that radiates down the leg, numbness around the anus, and loss of bowel or bladder control.

The tailfin of a fish and other aquatic vertebrates.

(zoology) Pertaining to the tail or posterior or hind part of a body.

A caudal vertebra.

(ichthyology) A lateral ridge found just anterior to each side of the tail fin on the caudal peduncle of some types of fast-swimming fish. The keels improve the stability of the fish's attitude at speed in the water, and strengthen the support of the caudal fin.

(ichthyology) The narrow part of a fish's body to which the caudal or tail fin is attached. Its proportions, such as the length and breadth, and attached organs, such as spines of surgeonfishes or caudal keels and finlets of Scombridae often are important in descriptions of fish species.